Die having textured inserts for manufacturing a textured mould for moulding and vulcanizing tires

Abstract

Die ( 1 ) representing a tread pattern model for a tread of a tire to be molded, said die being made up of a die body ( 2 ) and at least one insert ( 10 ) attached to the body of said die, covering at least one of the surfaces of the grooves ( 4 ) in the body ( 2 ), the insert having at least one substantially flat surface provided with textures.

The invention claimed is: 
     
       1. A die representing a tread pattern model for a tread of a tire to be moulded, said die comprising:
 a die body provided with one or more grooves, each groove having first, second and third flat surfaces arranged in planes separate from one another; and 
 at least one insert assembly, each at least one insert assembly being attached to a groove of the die body and comprising:
 a first insert attached to the first flat surface of the groove in which the at least one insert assembly is attached, wherein the first insert has at least one substantially flat surface provided with first textures, 
 a second insert attached to the second flat surface of the groove in which the at least one insert assembly is attached, wherein the second insert is assembled adjacent to the first insert in a first “L” shape and wherein the second insert has at least one substantially flat surface provided with second textures, and 
 a third insert attached to the third flat surface of the groove in which the at least one insert assembly is attached, wherein the third insert is assembled adjacent to the second insert in a second “L” shape and wherein the third insert has at least one substantially flat surface provided with third textures. 
 
 
     
     
       2. The die according to  claim 1 , wherein the insert assembly covers at least one of surfaces of tops of tread patterns on the die body. 
     
     
       3. The die according to  claim 1 , wherein the separate planes are disposed in a U shape. 
     
     
       4. The die according to  claim 1 , wherein at least two of said first, second and third textures are different from one another. 
     
     
       5. The die according to  claim 1 , wherein at least one of the first, second and third textures comprises a plurality of recessed or protruding elements formed integrally with said die. 
     
     
       6. The die according to  claim 1 , wherein all or some of the first, second and third textures are formed by cones distributed through the texture at a density at least equal to one cone per square millimeter (mm 2 ), each cone having a mean cross section of between 0.0005 mm 2  and 1 mm 2 . 
     
     
       7. The die according to  claim 1 , wherein all or some of the first, second and third textures are substantially mutually parallel striations, the spacing of the striations in the pattern being at most equal to 0.5 mm, each said striation having a mean width of between 0.02 mm and 0.5 mm. 
     
     
       8. The die according to  claim 1 , wherein all or some of the first, second and third textures form parallelepipeds having a side length of between 0.05 mm and 0.5 mm and a height of between 0.05 mm and 0.5 mm, the distance between two adjacent said parallelepipeds in the texture being between 0.05 mm and 0.5 mm. 
     
     
       9. The die according to  claim 5 , wherein the protruding elements form strands, said strands being distributed through the pattern at a density at least equal to one strand per square millimeter (mm 2 ), each said strand having a mean cross section of between 0.0005 mm 2  and 1 mm 2 . 
     
     
       10. The die according to  claim 5 , wherein the protruding elements form mutually parallel blades, the spacing of the blades in the pattern being at most equal to 0.5 mm, each said blade having a mean width of between 0.02 mm and 0.5 mm. 
     
     
       11. The die according to  claim 5 , wherein the recessed or protruding elements exhibit mutually variable shapes and distances. 
     
     
       12. A method for manufacturing a mould for moulding and vulcanizing tires, comprising the steps of:
 manufacturing the die according to  claim 1  having the one or more grooves; 
 disposing in each of the grooves the at least one insert assembly comprised of corresponding substantially flat surfaces provided with textures; 
 manufacturing, from the die provided with the at least one insert assembly, a mould comprised of flexible material corresponding to the negative form of the tire to be moulded; 
 manufacturing, from the flexible mould, a die comprised of brittle material, corresponding to the profile of the tire to be moulded; 
 manufacturing, from the brittle material die, a mould corresponding to the negative form of the tire to be moulded, made of metal material; and 
 removing the brittle material die so as to release the metal mould obtained. 
 
     
     
       13. The manufacturing method according to  claim 12 , wherein the textures of the inserts are manufactured by 3D printing or laser machining, or with the aid of punches, or by selective fusion of metal powder, or by electrical discharge machining. 
     
     
       14. The manufacturing method according to  claim 12 , wherein said flexible material is made of silastene and said brittle material is made of plaster.